The present invention concerns an automatic dispenser for ground coffee intended to be mounted on an automatic coffeemaker.
An example of an automatic dispenser is described in the patent document FR 2713906 and is composed of a reservoir containing ground coffee and means adapted to transfer, through a flow opening situated in a lower part of the reservoir, a dose of ground coffee into an infusion chamber of an automatic coffeemaker. The transfer, or dosing, means for the coffee grounds are constituted by several rotatable dosing paddles situated at the bottom of the reservoir and carried by a cylindrical body that is driven in rotation around the axis of the reservoir by a motor group. Four other upper radial paddles are carried by a coupling part having an outer conical form. The upper paddles are arranged just above the dosing paddles in order to cause the ground coffee to descend to the bottom of the reservoir, and the upper paddles are driven in rotation by the same means as the dosing paddles. The reservoir is removably mounted in the machine and coupling means are provided between the motor group and the cylindrical body for driving the dosing paddles and the coupling part. Although this device functions satisfactorily, it has been found that certain types of ground coffee have a natural tendency to agglomerate, or form clumps, within the reservoir, with the result of preventing the coffee grounds from descending to the level of the dosing paddles. This presents significant functioning problems above all in the case of an automatic coffeemaker when the infusion, or brewing, chamber is no longer correctly supplied.
One solution was described in the patent document DE 19714303 where the device for dosing the ground coffee comprises two levels of rotatable paddles and means for rotating them in respectively opposite directions. Thus, a lower section having a frustoconical form carries a first series of paddles and is extended toward the top by a conical point carrying, itself, a second series of paddles. The dosing device has first means for rotating the lower section and, between the latter and the mixer, second means permitting to reverse the sense of the first rotation and transferring it to the part at the tip of the cone. According to this document, these means consist of pignons and pulleys. While this device does provide a better movement of the grounds toward the bottom of the reservoir, it has as its main drawback a complex structure, rendering difficult the arrangement of the transmission mechanism in a small space that is limited by the dimensions of the conical part. Moreover, jamming phenomena can occur during infiltration of the grounds at the level of the interstice separating the two movable parts, the mixer and the lower section.